Re: [PATCH 05/20] cpu/hotplug: remove CPUHP_SLAB_PREPARE hooks

[Kees Cook <keescook@chromium.org>]

On Mon, Nov 13, 2023 at 08:13:46PM +0100, Vlastimil Babka wrote:
> The CPUHP_SLAB_PREPARE hooks are only used by SLAB which is removed.
> SLUB defines them as NULL, so we can remove those altogether.
> 
> Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
> ---
>  include/linux/slab.h | 8 --------
>  kernel/cpu.c         | 5 -----
>  2 files changed, 13 deletions(-)
> 
> diff --git a/include/linux/slab.h b/include/linux/slab.h
> index d6d6ffeeb9a2..34e43cddc520 100644
> --- a/include/linux/slab.h
> +++ b/include/linux/slab.h
> @@ -788,12 +788,4 @@ size_t kmalloc_size_roundup(size_t size);
>  
>  void __init kmem_cache_init_late(void);
>  
> -#if defined(CONFIG_SMP) && defined(CONFIG_SLAB)
> -int slab_prepare_cpu(unsigned int cpu);
> -int slab_dead_cpu(unsigned int cpu);
> -#else
> -#define slab_prepare_cpu	NULL
> -#define slab_dead_cpu		NULL
> -#endif
> -
>  #endif	/* _LINUX_SLAB_H */
> diff --git a/kernel/cpu.c b/kernel/cpu.c
> index 9e4c6780adde..530b026d95a1 100644
> --- a/kernel/cpu.c
> +++ b/kernel/cpu.c
> @@ -2125,11 +2125,6 @@ static struct cpuhp_step cpuhp_hp_states[] = {
>  		.startup.single		= relay_prepare_cpu,
>  		.teardown.single	= NULL,
>  	},
> -	[CPUHP_SLAB_PREPARE] = {
> -		.name			= "slab:prepare",
> -		.startup.single		= slab_prepare_cpu,
> -		.teardown.single	= slab_dead_cpu,
> -	},
>  	[CPUHP_RCUTREE_PREP] = {
>  		.name			= "RCU/tree:prepare",
>  		.startup.single		= rcutree_prepare_cpu,

Should CPUHP_SLAB_PREPARE be removed from the enum too?

-- 
Kees Cook